Mg–Sn Alloys as Anodes for Magnesium-Air Batteries

Three Mg–Sn alloys (with Sn contents of 1, 3, and 5 wt%) were investigated as anodes for magnesium-air batteries. The effect of Sn addition on the microstructure, electrochemical behaviour and battery discharge properties of Mg alloys was studied. Addition of Sn improves the operational voltage of Mg at low to high current densities. At low current densities ≤2 mA·cm −2 , Mg-5Sn exhibits better battery discharge performance than pure Mg and other Mg–Sn alloy anodes. At current densities higher than 5 mA·cm −2 , Mg-1Sn delivered the best battery discharge performance, evidenced by an anodic efficiency of 51.7%, specific capacity of 1133 mAh g −1 and specific energy density of 1208 mWh g −1 at 10 mA·cm −2 . The underlying mechanism by which Mg–Sn alloys improve Mg-air battery performance is discussed.